A CONNECTION BETWEEN SUBMILLIMETER CONTINUUM FLUX AND SEPARATION IN YOUNG BINARIES

We have made sensitive 800 mum continuum observations of low-mass, pre-main-sequence (PMS) binary stars with projected separations less than 25 AU in Taurus-Auriga to study disks in the young binary environment. We did not detect any of the observed binaries, with typical 3 sigma upper limits of approximately 30 mJy. Combining our observations with previous 1300 mum observations of PMS Taurus binaries by Beckwith et al. and others, we find that the submillimeter fluxes from binaries with projected separations a(p) between 1 and 50 AU are significantly lower than fluxes from binaries with a(p) > 50 AU. The submillimeter fluxes from the wider binaries are consistent with those of PMS single stars. This may indicate lower disk surface densities and masses in the close binaries. Alternatively, dynamical clearing of gaps by close binaries is marginally sufficient to lower their submillimeter fluxes to the observed levels, even without reduction of surface densities elsewhere in the disks.